Angle grinding pulp grinder

ABSTRACT

A grinder for making wood pulp wherein the logs are presented to the grinding face of the pulpstone with their longitudinal axes generally parallel to a plane that includes the line of tangency where the logs engage the pulpstone but with the axes of the logs at an angle to the axis of the pulpstone. The axes of the logs are turned at an angle of from about 2* to 30* to the axis of the pulpstone during grinding so that the sides of the logs are progressively disintegrated as the angularly disposed logs are pressed into the grinding wheel.

United States Patent Inventor James H. Perry Worcester, Mass. 822,539

May 7, 1969 Oct. 12, 1971 Norton Company Worcester, Mass.

Appl. No. Filed Patented Assignee ANGLE GRINDING PULP GRINDER Primary Examiner -Donald G. Kelly Attorney-Allan R. Redrow ABSTRACT: A grinder for making wood pulp wherein the logs are presented to the grinding face of the pulpstone with their longitudinal axes generally parallel to a plane that includes the line of tangency where the logs engage the pulpstone but with the axes of the logs at an angle to the axis of the pulpstone. The axes of the logs are turned at an angle of from about 2 to 30 to the axis of the pulpstone during grinding so that the sides of the logs are progressively disintegrated as the angularly disposed logs are pressed into the grinding wheel.

PATENT ED um I 2 I971 ATTORNEY BACKGROUND OF THE INVENTION 'II-Ie grinding of logs to produce wood pulp for the making of paper, paper board and other products is a well-known art. Abrasive pulpstones have been used for this for a number of years. Inthe past, various means have been used to push the logs against the stones and invariably it has been the practice to feed the logs under pressure against the surface of the rotating stone, with the axis of the log to be ground, generally parallel to the axis about which the pulpstone rotates. Under the proper conditions of heat and pressure, in the presence of water, the log is acted on by the abrasive surface of the pulpstone so that the individual fibers of the wood are freed from the log either singly or in bundles, hopefully with a relatively small percentage of damaged or broken fibers. Many experiments have been made to determine the proper pressure, temperature, condition of the surface of the stone etc. to improve the quality of the pulp produced. The present invention provides an improvement in the mode of delivering the log to the stone to obtain improved quality in certain attributes of a paper product resulting from use of the pulp produced.

BRIEF DESCRIPTION OF THE INVENTION The present disclosure takes the form of a feeding arrangement for receiving logs disposed in a parallel arrangement to be pressed against the surface of a grinding wheel and includes wedge or cam means over which the ends of certain of the logs pass as they are pushed forwardly in a pocket to turn all of the logs to the proper angle as they approach the grinding wheel. The log-engaging means are made to be adjustably positioned in the feed pocket so that as the sides of the logs move toward the grinder the ends of some of the logs are engaged to cause the logs to be turned to the desired angle for presentation to the grinding wheel.

In the conventional feed pocket of a pulpstone grinder, the cam or guide means may take the form of wedges mounted on diagonally opposed top and bottom sides of the pocket. The position of the wedge or guide is preferably adjustable so that the logs passing through the pocket and being guided by these means may be turned to the angle considered best for the type of wood being ground or the kind of pulp to be produced.

The other elements of the grinder remain the same, the structure for turning the logs and the method for angular grinding of logs constituting the invention disclosed herein.

IN THE DRAWINGS FIG. I shows a sectional side elevation of one pocket of a typical hydraulic pulp grinder;

FIG. 2 is a view taken along line 2-2 of FIG. 1; and

FIG. 3 is a detail view taken on line 3-3 of FIG. 2 but turned into a vertical position.

DETAILED DESCRIPTION The typical construction of a pulp grinder is well known as may be seen in U.S. Pat. No. 1,975,452 issued Oct. 2, 1934 to Farley. Such a grinder includes an abrasive pulpstone mounted to be rotatably driven about a horizontally disposed axis II, by motor and drive means not shown. The pulpstone may be 75 inches long and have a diameter of up to 90 inches. Spaced around the periphery of the pulpstone are one or more stationary pockets each within a housing 12 that are adapted to hold logs 13 that are being pushed against the grinding wheel by a piston 14, driven by suitable pressure-applying means, not shown. Conventional shower means 15 and 16 are provided at the opposite sides of the pocket, shower 15 to provide a proper coating of ,water on the surface of the wheel to assist in the grinding action and shower 16 serves primarily to clean the surface of the wheel and cool the wheel as it moves from the grinding zone of one pocket and toward the grinding zone of the next pocket.

It hasbeggh practice heretofore to press'logs against the pulpstone with their axes as nearly parallel to the axis of the grinding stone as is possible. I have found, however, that if the .logs are presented to the surface of the grinding wheel at a cross angle, that a different type of fiber separation is accomplished such that it is a slower draining pulp, but the fibers have unusually good strength whereby a better quality of pulp results. Paper made from such pulp will be found to have improved burst and tear characteristics.

To accomplish the proper positioning or angular disposition of the log with respect to the surface of the pulpstone I place wedge or cam means 20 and 21 at the diagonally opposite corners of the pocket 12 adjacent the open end of the pocket from which the logs move into contact with the surface of the grinding stone 10. It will be seen that as the logs in the pocket -are pushed forwardly the near end of the logs moving along the bottom of the pocket as in FIG. 1 or the left end of those logs referring to FIG. 2, ride up on cam 20. At the diagonally upper corner of the pocket, near the surface of the grinding stone, the far end of the top logs as seen in FIG. 1 or the righthand end of those logs as seen in FIG. 2 pass under guide means or cam 21. Therefore, as the logs approach the grinding wheel surface because of the force applied by piston I4, the logs roll over upon themselves and adjust to the angular position desired as they issue from the free end of the pocket to be engaged on the grinding surface.

The cam surfaces 20 and 21 are removably mounted in the .pocket so that any desired angular disposition of the log against the surface of the grinding stone can be accomplished.

'-It is suggested that the logs can be presented throughout a range of angles of from approximately 2 to a maximum of 30. In practice, the angle at which the wood is turned to I produce the best result is dependent upon the condition of the wood, the kind of wood being ground and the use to which the pulp is to be put. For newsprint, a large proportion of individual fibers are best and the logs should be presented to the pulpstone with their axes turned at an angle of about 8 to the axis of the grinding wheel. If a rougher texture pulpboard is to be produced, the desired pulp will be produced by turning the logs so that their axes will be disposed at about 30 with respect to the axis of the grinding wheel. To accomplish such variation in angular control of the logs, the cams 20 and 21 must be made interchangeable, or otherwise made to be adjustably mounted at the opposite sides of the outlet end of the feed pocket to the surface of the grinding wheel.

As stated above, the conventional grinder usually has more than one pocket to receive wood. It is obvious that the same cams are provided for each pocket so that all the wood being ground will be uniformly turned at the same angle for presentation to the grinding surface.

In typical grinding operations spruce was ground in a conventional pulp grinder in which the logs were turned at an angle of 8 to the axis of the pulpstone while being pressed against the surface of the stone, the following data were tests.

All other factors of grinder operation being maintained the same insofar as possible, it is seen that a pulp is produced that is stronger in several respects. It was observed also that the pulp had a better brightness.

Similar results have been observed produce a pulp.

While the above describes the preferred form of my invention, it is apparent that many modifications thereof may occur to those skilled in the art which will fall within the scope of the following claims.

lclaim:

l. A method of making pulp by separating elongated fibers from a source of wood comprising rotatably driving a pulpgrinding wheel about a given axis forcibly pressing the wood to be ground against the surface of the stone while simultaneously holding the wood so that the elongated fibers on the surface thereof are in a generally tangential relationship to the surface of the wheel but with the longer axes of the fibers at an angle to the axis about which the wheel rotates and wherein when grinding fir to said angle of fiber disposition is between 2 to 30 from the' parallel relationship to said axis about which the wh ee l rotates.

2. A method as in claim 1 wherein said angle of fiber disposition is about 8 from a parallel relationship.

3. Apparatus for grinding logs to produce fibrous pulp comprising an abrasive grinding wheel, means for rotatably mounting and driving said wheel, a pocket for receiving logs disposed in parallel relation to be fed against the surface of said wheel with their longitudinal axes ultimately being substantially tangent to the wheel surface as the logs are each individually ground away and the longitudinal axes of the logs also being disposed at an angle to the axis of the wheel, a pressure-applying means for forcibly engaging said logs against the surface of said wheel, said pocket for receiving the logs being a chamber of rectangular cross section having an open end facing the wheel, and guide means in the form of cams disposed at diagonally opposite corners of said open end for engaging the logs to produce the desired angular relationship between the axes of the logs and the axis of the wheel.

4. The apparatus of claim 3 wherein said guide means are variable to select the desired angular relationship.

5. The apparatus of claim 3 wherein said guide means are variable to select the desired angular relationship to turn the logs so that their longitudinal axes will be turned to an angle with respect to the axis of the wheel that falls within a range of from 8 to 30 from a parallel position.

Disclaimer 3,612,413.James H. Perry, Worcester, Mass. ANGLE GRINDING PULP GRINDER. Patent dated Oct. 12, 1971. Disclaimer filed May 24, 1972, by the assignee, Norton Company. Hereby enters this disclaimer to claims 1 and 2 of said patent.

[Ofiieial Gazette September 19, 1.972.] 

2. A method as in claim 1 wherein said angle of fiber disposition is about 8* from a parallel relationship.
 3. Apparatus for grinding logs to produce fibrous pulp comprising an abrasive grinding wheel, means for rotatably mounting and driving said wheel, a pocket for receiving logs disposed in parallel relation to be fed against the surface of said wheel with their longitudinal axes ultimately being substantially tangent to the wheel surface as the logs are each individually ground away and the longitudinal axes of the logs also being disposed at an angle to the axis of the wheel, a pressure-applying means for forcibly engaging said logs against the surface of said wheel, said pocket for receiving the logs being a chamber of rectangular cross section having an open end facing the wheel, and guide means in the form of cams disposed at diagonally opposite corners of said open end for engaging the logs to produce the desired angular relationship between the axes of the logs and the axis of the wheel.
 4. The apparatus of claim 3 wherein said guide means are variable to select the desired angular relationship.
 5. The apparatus of claim 3 wherein said guide means are variable to select the desired angular relationship to turn the logs so that their longitudinal axes will be turned to an angle with respect to the axis of the wheel that falls within a range of from 8* to 30* from a parallel position. 